This is my first encounter with Gentoo/Sabayon and I am enjoying it so far, but it is different.My question is, how do I get my Napster library to play in Sabayon or XBMC? When I try to access it through a browser it just hangs. Any suggestions welcome.

Don't use Napster myself, but Google appears to indicate that you could set up a SHOUTcast server on your PC to stream audio to XBMC. For details of how to set up SHOUTcast with Gentoo/SL, see Streaming Radio With SHOUTcast. Doesn't look simple.

You will need to install the packages media-sound/shoutcast-server-bin and media-sound/shoutcast-trans-bin, neither of which are in Entropy at the moment. You could put in a request via the SL Bugzilla (see the link Bugs at the top right of this page) for these two packages to be added to the Entropy repository, or, alternatively, you could install them via Portage as root user in a Konsole/Terminal window: